iMac C2D 2.16 3GB vs. PowerMac G5 2x1.8 8GB?

I currently have a 24" white iMac Core 2 Duo 2.16GHz with 2GB of RAM. I am getting kind of frustrated at its upgrade limitations. I can only go up to 3GB of RAM, and the CPU and HDD cannot be upgraded. I do however love the 24" screen. It works beautifully for everything except for iPhoto. Loading RAW files from my 5D is mind-suckingly slow. I am not even talking of editing or anything, I mean just scrolling through my library. (My iPhoto library is on an external FW400 drive, a 7200rpm 1.5TB Seagate -- the internal 250GB drive is just not big enough.)

I am thinking of purchasing a used PowerMac G5 to replace the iMac. The CPU will be slower, but I can add up to 8GB of RAM, which seems to be the bottleneck in my current system. (Also I can have 2x internal hard drives which should speed things up as well.) Every time I look at top (command line) or Activity Monitor (GUI) it shows pretty much all 2GB being used no matter what I am doing, while the CPU is usually not terribly loaded. I could get the upgrade to 3GB, but I am wondering if that would be enough.

I was just wondering if any of you had any input based on your experiences. Clearly my best bet is to go to a Mac Pro, but I don't have the cash for that right now, so basically I am just wondering whether the potential quadrupling of RAM will balance out the slower CPU's. I am thinking of buying a 2x1.8GHz PM G5 that is for sale locally.

I have a 2x2GHz G5 with 5.5 Gb Ram, a 160Gb and 320Gb HDD (less then 1/2 full).
A current MBP is faster for LR for instance... Might be different when editing big files in PS. (I've occasionally edit layered files that go north of 2Gb, not exactly fast, but usable)

Have a look in the Benchmark Photoshop Speed Test...

Post #2 and 25 are a G5. Post 56 is an iMac (which is about 25% faster)

Thanks for the link, those are some interesting benchmarks. PS isn't my problem necessarily, but it is good to see the 2 systems compared directly, which I admit is somewhat odd (iMac vs. PM G5). Thanks also for your input on your G5 vs a MBP. I might just have to go up to 3GB in my iMac and see if that helps. Also I should probably try Lightroom or Aperture instead of iPhoto. Updating to iPhoto '09 might also make a difference....

I have the same iMac as you do. You now understand why I built a quad-core hackintosh.

I have been thinking fairly seriously about a Hackintosh. I already have a motherboard that I think should work reasonably well (Asus P5B -- Intel P965 chipset) so it's a matter of finding a good compatible video card and running with it.

another option is to work with what you have? how full is your mac hd?
how many photos do you want to look at at one time? 100 or 4000? if 100 it might be easier to drop them into a folder on your mac hd for usage.

Do you have another way of viewing your files other than iphoto that you can try?
I haven't used iphoto in years so don't really know how good that app is any more, but years ago it used to double every image, so double the space it used. It also had the worst configuration for storing images. so to find them in the system was a nightmare.

My HDD is 250GB, my iPhoto library is 247GB, just the originals (RAW files) are almost 200GB. Even if I used a more space-efficient program (iPhoto does make multiple copies of each photo, but they're usually smaller in size than the original), I still wouldn't be able to fit everything on the internal HDD, and moving stuff is a hassle. (Note: I tried taking apart the iMac to upgrade the internal HDD, and my Torx screwdriver wasn't long/thin enough to get past taking off the outer casing-- there are some pretty deeply recessed Torx screws in there.) I tried doing the "archive" thing, moving older stuff over from time to time, but it doesn't work very well. Actually I think the FW drive is the least of my worries. FireWire is a good fast connection.

I think I will try a RAM upgrade to 3GB and maybe a demo of Aperture to see if it's any faster. Also I will work forward on the Hackintosh.